Risk characterization of microplastics in San Francisco Bay, California

Coffin, Scott; Weisberg, Stephen B.; Rochman, Chelsea; Kooi, Merel; Koelmans, Albert A.

doi:10.1186/s43591-022-00037-z

Microplastics and Nanoplastics

Table 1 Summary of correction factors applied probabilistically to samples from SFB

From: Risk characterization of microplastics in San Francisco Bay, California

Sampling Apparatus	Matrix	Mesh Size (μm)^a	Alpha (unitless; median, 5th to 95th percentiles)	CF^b (unitless; median, 5th to 95th percentiles)	Proportion of Particles Confirmed Plastic (unitless; median, 5th to 95th percentiles; probability distribution)	Fiber Correction Factor (unitless; median, 5th to 95th percentiles; probabilty distribution)	Combined Correction Factors (unitless; median, 5th to 95th percentiles)
1-L grab	Surface water	50	2.07 (2.02 to 2.12)^c 2.15 (1.36 to 2.93)^d	66 (55 to 80)^c 90 (5 to 1988)^d	0.40 (0.19 to 0.72) beta: shape 1 = 6.03, shape 2 = 137	NA^f	26 (12 to 48)^c 35 (1.7 to 823)^d
24-hr pipe	Stormwater	106	2.97 (1.62 to 4.35)^d	9361 (20 to 6,120,045)^c	NA^e	NA^f	9361 (20 to 6,120,045)^c
Composite	WWTP effluent	110	2.54 (2.52 to 2.56)^c 2.41 (2.18 to 2.64)^d	1396 (1292 to 1507) 762 (256 to 2290)^d	0.27 (0.09 to 0.64) beta: shape 1 = 3.00, Shape 2 = 93.5	NA^f	384 (119 to 888)^c 202 (44 to 825)^d
Manta Trawl	Surface water	333	2.07 (2.02 to 2.12)^c 2.15 (1.36 to 2.93)^d	529 (401 to 704)^c 797 (12 to 73,349)^d	0.72 ± 0.24 (65) beta: shape 1 = 5.81, shape 2 = 73.7	9 (1 to 52) Normal (log10-transformed): mean = 0.965, stdev = 0.529	2819 (336 to 17,966)^c 4103 (41 to 554,392)^d
Otter trawl/cast net	Biota^c / fish tissue^d	25	2.59 (2.52 to 2.66)^c 2.26 (1.92 to 2.60)^d	167 (135 to 2066) 58 (20 to 1750)^d	0.23 (0.09 to 0.46) beta: shape 1 = 4.20, shape 1 = 169)	NA^f	38 (14 to 80) 13 (3 to 49) ^d
Van Veen Grab	Sediment	45	2.57 (2.24 to 2.90)^c 2.90 (2.22 to 3.59)^d	394 (113 to 1398)^c 1342 (103 to 18,861)^d	0.34 (0.16 to 0.69) log-normal: meanlog = −3.39, sdlog = 0.44	NA^f	133 (32 to 553)^c 454 (31 to 6860)^d

^aConcentrations were rescaled to 1 to 5000 μm
^bExact mesh size values as reported in Zhu et al. [70] were used to rescale data
^cValues from Kooi et al. [37] and derived from various locations in Europe. Alpha values for stormwater have not been reported elsewhere in the literature. Alpha value reported for biota in Kooi et al. [37] are primarily polychaetes
^dDerived using site-specific data for San Francisco Bay obtained from Zhu et al. [70]
^eStormwater particle-level data were not reported in CEDEN and could not be obtained to perform this analysis
^fFibers were only systematically removed from manta trawl samples, so fiber correction factors are not applicable for other sampling apparatuses

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